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Problem with Joule-Heating simulation in a high aspect-ratio system |
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November 28, 2012, 16:27 |
Problem with Joule-Heating simulation in a high aspect-ratio system
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#1 |
New Member
Join Date: Nov 2012
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Hello,
I have a problem with a code which I have written to simulate Joule-Heating through a 3D cubic system made of silver. When the aspect ratio between l_x/l_y (l_x and l_y are the length of the system in x and y direction) is less than 100, I get good results from the code independent of the number of grid points generated in the system. However, when the l_x/l_y is larger than 100, the temperature distribution predicted by the model shows deviations from a true symmetric distribution for even 30000 grid points which are not really large. What could be the problem? I have used a resistive networks to solve electrical and heat conduction equations. I appreciate for any help. Farshad |
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November 29, 2012, 04:28 |
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#2 |
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Rami Ben-Zvi
Join Date: Mar 2009
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Hi Farshad,
Rami
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November 29, 2012, 07:57 |
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#3 | |
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Quote:
Thanks for your answer. I am using our in-house code which is basically a Finite-Difference code. I think you are right. Because I try to shrink the aspect ratio of the grids in the high-aspect ratio case and now it's giving me the right answer. Lz/Lx = 1. Thanks again, Farshad |
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November 30, 2012, 13:00 |
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#4 | |
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Quote:
Is there any mathematical rule or basis for choosing the correct value for the time step as well as grid boxes for large geometrical aspect ratio? Farshad |
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December 4, 2012, 04:09 |
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#5 |
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Rami Ben-Zvi
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The time step should be selected by considering stability and accuracy. The stability depends on the scheme you use, and - if your boundary conditions, initial conditions and sources are extremely time- or space- dependent (e.g., have discontinuities of high derivatives) - they may also influence stability. Accuracy is usually improved by smaller time-steps. The aspect ratio is implicitly dealt with when considering the characteristic length for stability.
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